Now that you mention it, Luffy was a walking L pre timeskip.
He lost to Smoker, lost to Crocodile twice, lost to Lucci, lost to Magellan, lost to Kuzan, lost at Sabaody. Got wrecked at marineford. Only loss post timeskip was Kaido.
With that said we know Kaido has only lost in battle 7 times. If I was to guess he probably lost to Roger, Whitebeard, Garp, Sengoku, Big Mom and probably Shanks when he intercepted Kaido to prevent him from showing up at marineford.
and the point of the paramount saga and lost to Lucci was to drive home the point that he needs to get stronger.
since the beginning of part 2 hes become to strong for some and has been given the powerups to beat and match his opponents that are to strong like G4, Future sight, and now extra CoA abilties.
I have no issues with it. But to act like OP dont be doing power ups is absurd
this series has had several mid fight/action powerups from Zoro, Luffy, Sanji, Usopp, Chopper, etc
and im just talking mid fight ones, not ones in general like Zoro getting a cursed sword or Ryumas, or Usopp getting dials, Nami getting stronger clima tacts, etc.